Originally, you needed to compile your GNU/Linux system manually from source, which used to be time consuming and could be problematic if you couldn't get your dependencies straight. Red Hat created Red Hat Package Manager (RPM) in 1998 to address the concerns of dependencies and reduce the time needed to install a system (among others). Since then, RPM has been improved by the Open Source community. One such improvement is yum.

Yellowdog Updater, Modified (yum) is a package management tool using RPM. It allows RPM to access remote repositories of RPM files and will automatically download the required RPM files based on the dependency information provided by RPM.

Without a Red Hat Network subscription, you will not get access to updates.

Besides Red Hat Network, you can purchase Red Hat Satellite if you want even more control of your Red Hat systems.